Analysis of the use effect of Decanter centrifuge:

1) In the past, the volume of the biogas tank built by the farmer was too small, and the drainage time after the sewage entered the tank was too short, resulting in excessive discharge of sewage concentration. Use the decanter centrifuge to process the sewage before it sinks into the pool, which can effectively reduce the COD and BOD content of the sewage, reduce the operating load of the biogas digester, and thus achieve the reduction of sewage discharge;

2) The use of decanter centrifuge in advance can transform the feces in the fresh sewage into valuable fish feed or organic fertilizer. The separated sewage intermittently enters the biogas digester, so that the anaerobic digester can have a full digestion time, so that the active bacteria in the digester can reproduce more vigorously, the gas production is higher, and the content of gas methane is naturally higher High purity will be overcome naturally to solve the problem of abnormal operation of biogas generators;

3) The sewage treated by the decanter centrifuge enters the biogas digester, which can effectively solve the crust phenomenon of the biogas digester and eliminate the work of cleaning the biogas residue;

4) The use of decanter centrifuge can reduce the investment in the construction of biogas digesters, for example: a breeding or slaughterhouse that discharges 100 tons of sewage per day. If a matching decanter centrifuge is used for pre-treatment, it can reduce the 300 cubic anaerobic tank Construction investment, because the concentration of manure and sewage mixed into the pond is too high, the anaerobic time will need to be extended accordingly, so if a farm that discharges 100 tons of sewage per day, without decanter centrifuge treatment, then an anaerobic pond 1000 is needed -1200 cubic meters, if using decanter centrifuge can reduce the construction of 300-400 cubic meters.

 If the materials processed by the Decanter centrifuge contain flammable and explosive substances such as organic solvents, the centrifuge should have explosion-proof performance. The explosion-proof performance is determined according to the explosion-proof requirements of the process. The explosion-proof occasions involved in the past have only been proposed to be equipped with explosion-proof motors. In the past two years, most of the occasions where the processed materials contain organic solvents such as solvents have been required by nitrogen protection. In fact, to realize the explosion-proof in the true sense, centrifuges must take various measures in mechanical, electrical control, accessory configuration and other aspects.

For instance: electric control system: explosion-proof isolation barrier, non-contact energy consumption braking system, electrostatic grounding, automatic control of explosion-proof.

Mechanical system: explosion-proof motor, explosion-proof lighting, anti-collision measures, anti-static transmission belt.

Explosion-proof accessories: nitrogen protection device, nitrogen online detection, on-site explosion-proof control button.

GN Explosion proof electrical control panels or electrical control stations are used in hazardous Location. The Ex control panel is designed and built to operate in environments where concentrations of flammable gases, vapors, liquids or combustible particles pose risks of ignition and explosion. GN Solids Control provide explosion proof control panel with ATEX approval, IECEX Approval, China National explosion proof approval. The protection degree is up to IP65 for weather and dust proof.

GN explosion proof control panel enclosures are cast from heavy duty aluminum so that they cannot create a spark that could possibly ignite the vapors in a hazardous location. These heavy duty panels come with seals keep explosive fumes from entering the control panel. Moreover the GN explosion proof control panels are designed to contain an internal explosion without igniting the explosive vapors present in the hazardous area to make sure it is safe for the hazardous Zone 1 or Zone 2 areas.

GN Explosion Proof Pressurized Control Panel is popular used for VFD controland soft starter of motor, especially in high temperature ambient. The explosion proof pressurized control panel consists of main cavity and auxiliary cavity. The main cavity is pressurized cavity which includes electrical components, pressure check sensor system, ventilation air distribution system, and air conditioning system. The purging system works automatically to maintain a certain positive pressure inside the main cavity.

GN Solids Control is capable to provide you with IEC Ex, ATEX or CNEx Standard Positive Pressurized Control Panel control panels with Zone 1 or Zone 2 for hazardous locations. This will also suit the North America Class I Division 1 or Division 2 hazardous locations application.

Decanter centrifuges are often used in severe environment and under high workload, so problems will occur sometimes and the decanter centrifuge has to be serviced or repaired. How can we maintain the centrifuges? Here is your answer:

1. When the decanter centrifuge is in the pre-cooled state, the centrifuge cover must be closed. After the centrifugation is finished, the rotor is removed and placed on the experimental table. The remaining water in the chamber is dried and the centrifuge cover is open.

2. The rotor cover can be placed on the platform of the decanter centrifuge or on the experimental table during pre-cooling. Never float the rotor on the rotor without tightening it, because the rotor cover will fly out and cause an accident!

3. After tightening the rotor cover, be sure to touch the gap between the rotor and the cover with your fingers after tightening. If there is a gap, unscrew it and tighten it again.

4. During the centrifugation process, the operator must not leave the centrifuge room. In the event of an abnormal situation, the operator cannot turn off the power. Press STOP. Fill in the centrifuge record before pre-cooling.

5. Do not use inferior decanter centrifuge spare parts, or use aging, deformed or cracked centrifuge drums.

6. You can leave only after the last routine safety check using a centrifuge on holidays and evenings.

7. When a failure occurs during the operation of the decanter centrifuge, please contact the technical staff in time when the component is damaged.

GN design and manufacture different size of decanter centrifuge for industry separation with 12 years experience. And GN products have been exported to more than 70 countries with reliable quality and service. Welcome to inquire and visit GN and we are looking forward to cooperate with the clients all over the world.

The production capacity of the decanter centrifuge depends on the density difference between the solid and liquid phases and the length of the sedimentation zone. The closer the density difference between the solid and liquid phases and the higher the viscosity of the slurry, the more difficult to separate and settle. In actual production, there are three main factors that affect the separation effect of the decanter centrifuge: the feed temperature, feed rate, and abnormal process conditions.

     A. Feeding temperature: The temperature of the slurry can directly affect the viscosity of the mother liquor. Generally speaking, the higher the solution temperature, the lower the viscosity, the thinner the liquid film on the solid phase, and the easier the fine particles to settle. And the liquid in the pores will be less.

     B. Feeding rate: Sometimes, large feeding amount will lead to poor separation effect, mainly because the sedimentation time of the particles in the drum of decanter centrifuge is not enough. The premise of achieving the separation conditions designed by the decanter centrifuge is that the time for the solid particles to settle on the drum wall must be less than the residence time of the particles in the drum. The effective residence time of the slurry to be separated in the drum must be guaranteed, So that the solid particles have enough time to settle out. In our practical experience, the separation effect is not good when the feed volume is 1m3 / H for the same material, but when the feed volume is 0.5m3/h, the separation effect will be ideal .

C. Abnormal process conditions: mainly refers to the insufficient crystal content in the feed slurry or the crystals are not crystallized but flocculated, which is very difficult for the decanter centrifuge to obtain the ideal separation effect.   

By the way, if you are interested in our products, please check the following items of our company on Alibaba:

Decanter centrifuge

3–Phase Disc centrifuge

Sludge dewatering Screw press

Oil water separator

Centrifugal pump

Vacuum Pump

Submersible pump

The screw is the main component of the Decanter centrifuge. Its function is to transport the sediment deposited on the inside of the drum and smoothly discharge the sediment. It is not only the unloading device, but also determines the production capacity, service life and separation effect.

The type of screw is divided into counter-flow type and down-flow  type according to the relative movement of liquid and solid in the drum.

The feeding chamber of the counter-flow Decanter centrifuge is located in the middle of the spiral, that is, near the boundary between the drying zone and the sedimentation zone, to ensure that the liquid phase has a sufficient sedimentation distance, but the solid phase can only stay for the time required to pass through the cone. Therefore, a high centrifugal force is required; entering the drum from here will cause the solid particles that have settled in this area to float again due to disturbance, and turbulence and additional vortices will be generated, which will reduce the separation effect.

The down-flow decanter Decanter centrifuge has a feed inlet at the end of the drum, which avoids counter-flow turbulence and ensures that the sediment is not disturbed. The entire length of the decanter centrifuge is settled, expanding the settlement area, and the residence time of the suspension in the machine. So that the separation effect is improved. The prolonged and undisturbed sedimentation can effectively reduce the amount of flocculant used, greatly improve the fluid flow state in the machine, and increase the centrifugal force by increasing the diameter of the drum, so it can significantly reduce the speed and save power consumption. At the same time, reduce noise and extend the life of the machine.

The down-flow screw structure of decanter centrifuge is especially suitable for difficult-to-separate materials with small solid-liquid density difference, poor solid-phase sedimentation performance, and low solid-phase content. However, the filtrate of the down-flow decanter centrifuge is discharged through the skimming tube. The solid particles that are not separated when the filtrate passes through the skimming tube will be separated and deposited in the skimming tube. The skimming tube channel will be blocked after a long time operation, so it needs to be washed regularly.

In recent years, with the increasing requirements for sludge dewatering, efficient screw structures have emerged. For example, weir plate technology, a special baffle is set at the spiral discharge end of the cone section of the decanter centrifuge, which can put the centrifuge in an ultra-deep liquid pool state to increase the slagging force on the mud cake, and only convey the lower sediment, and The sludge with high moisture content in the upper part is trapped on the outside of the crushing cone section to realize dehydration and make the sludge drier.

There are many types of decanter centrifuges, and each type has different characteristics and scope of application. Therefore, it is a very important issue to properly select the appropriate decanter centrifuge according to certain process requirements and technical conditions. The selection of decanter centrifuge is mainly considered from two aspects. The first is the nature, composition of the separated materials, and the second is the technological requirements and economic rationality of the separation process:

I. Consider from the nature and composition of materials

The primary basis for selection is the type of heterogeneous system that is separated. For example, for the separation of emulsions in a liquid-liquid system, the first consideration is to use a centrifugal separator. For liquid-solid systems, when the liquid phase of the suspension is a loose material with a low degree of solidity, large solid phase concentration, and coarse particle size (> 100um), various filter decanter centrifuges can be considered. Generally speaking, this kind of decanter centrifuge can get drier filter residue and better washing conditions. Secondly, it is necessary to further select the appropriate form for specific conditions.
If the suspension is a material with a large liquid phase viscosity and a fine solid particle size, it is easy to block the filter cloth or screen, but it is difficult to regenerate. Therefore, a centrifugal sedimentation decanter centrifuge should be used. When the solid phase concentration is large (5% to 10%), a spiral discharge sedimentation decanter centrifuge can be used. If the solid phase concentration is less than 1%, a tubular high-speed decanter centrifuge or a chamber decanter centrifuge can be used. If the solid phase concentration is 1% — 5%, a disc decanter centrifuge can be used. The automatic slag-discharging dish decanter centrifuge can obtain flowing concentrated sediment, so it is often used for solid-phase concentration. For liquid-liquid-solid three-phase systems, generally the solid content is not high, you can use a dish decanter centrifuge.

2, from the technical requirements of the separation process

The process requirements of the separation process directly affect the selection of the decanter centrifuge. For example, the separation process requires intermittent or continuous operation. The minimum particle size of the separation, the liquid content of the filter residue, the clarity of the filtrate, the discharge method, whether the solid particles are allowed to be destroyed, and washed Requirements, the length of the operating cycle and whether automatic control is required, the degree of automatic control, etc.
In addition, there are still requirements for sealing, anti-corrosion and explosion-proof.
In short, it is necessary to choose a decanter centrifuge that is inexpensive, applicable (that is, in line with process requirements), simple to manufacture, and easy to maintain. Choose according to the main contradictions that need to be resolved and make economic comparisons. Both technical possibilities and economic rationality must be considered. Of course, according to human operation, there are also manual operation and automatic operation. Users can choose according to their needs.

The thickness of the liquid–ring layer is an important parameter for the optimization of Decanter centrifuge, which directly affects the effective settling volume of the decanter centrifuge and the length of the drying area (shore area), and then affects the sludge dewatering treatment effect. Generally, it is realized by manually adjusting the height of the liquid level baffle in the stop state. When adjusting, the height of each liquid level baffle must be consistent, otherwise it will cause severe vibration during the operation of the decanter centrifuge, and some foreign manufacturers’ products can realize automatic adjustment of liquid-ring layer thickness.

By increasing the thickness of the liquid–ring layer will increase the sedimentation area and the residence time of the material in the Decanter centrifuge will increase accordingly. The quality of the filtrate will be improved as well. On the contrary, by lowering the thickness of the liquid-ring layer can obtain a higher mud cake of solid content, but this will be at the basic of the filtrate quality lost.

Therefore, the height of the liquid level baffle should be adjusted reasonably to achieve the best combination of mud cake degree and filtrate quality. In general, many decanter centrifuge suppliers have adjusted the liquid level baffle in advance when the machine leaves the factory. However, due to different conditions on the site, if the operating status of the decanter centrifuge is not ideal, you can communicate with the equipment engineer to make adjustment to the on-site liquid level baffle.

GN can not only provide users with Decanter Centrifuges, but also provide users with turnkey solutions for dewatering process, including solutions for material transportation, classification and dewatering. Rely on GN’s rich production line of separation and conveying equipment, more and more reliable and advanced equipment will be manufactured for users all over the world.

Difference between solid-liquid & solid-liquid–liquid separation by decanter centrifuge

In the processing and selection of decanter centrifuge, it is sometimes necessary to judge whether solid-liquid two-phase separation can be completed in case of accident due to the difference of properties of materials to be separated, or whether liquid can be divided into light liquid and heavy liquid needs solid-liquid three-phase separation. This delineates the need for solid-liquid separation using two-phase separation or solid-liquid-liquid three-phase separation of decanter centrifuges.

The two-phase decanter centrifuge consists of frame, cover, main bearing, drum, screw, differential, drive system and control system. The drum and the screw rotate at the same direction and high speed at different speeds. The material enters the inner cylinder of the screw through the feed pipe and enters the drum from the feed port.

Under the action of centrifugal force, the heavy solid-phase materials are deposited on the wall of the drum to form a sediment layer, and the spiral continuously pushes the deposited solid-phase materials to the cone end of the drum, which is discharged out of the machine through the slag discharge port. The lighter liquid phase materials form an inner liquid ring, which overflows the drum continuously from the overflow port at the big end of the drum, and is discharged out of the machine through the discharge port.

The three-phase decanter centrifuge is mainly used for solid-liquid-liquid separation, that is, separation of one solid phase (high density) and two liquid phases with different densities. The drum and the screw rotate at the same direction and high speed at different speeds. The material enters the inner cylinder of the screw through the feed pipe and enters the drum from the feed port.

Under the action of centrifugal force, the solid phase material is deposited on the wall of the drum to form a sediment layer, and the two liquid phase materials form a light liquid phase ring and a heavy liquid phase ring respectively. From the wall of the drum, the solid phase layer, the heavy liquid phase layer and the light liquid phase layer are successively formed inward.

The solid materials deposited on the drum wall are continuously pushed to the cone end of the drum by the screw and discharged out of the machine through the slag discharge port. The light liquid phase and heavy liquid phase overflow continuously from different overflow ports at the big end of the drum, so as to realize three-phase separation.

GN 3 Phase Decanter Centrifuge Shipped to Middle East for Oily Wastewater Treatment

News from GN company this week: Recently, 1 set of 3–Phase Decanter Centrifuge have been manufactured and ready to start serving for a project in Middle East for Oily Wastewater Treatment.

GN 3–Phase Decanter Centrifuge is mainly designed for Solid-liquid-liquid three-phase separation of materials.With our over 10 years of experience in the separation industry, it is the most advanced type machine for 3 phase separation. It is designed for 24 hours continuous and smooth operation throughout the day. It is mainly composed of driving system, decanter bowl, screw conveyor inside the bowl, cover box, skid and VFD control panel.

To make sure the 3–Phase Decanter Centrifuge will provide a reliable performance and the parts and components of all the equipment will run smoothly for a long term operation, our technical department, production department and quality control department have paid a lot of attention to the material selection, material preparation, every step of production and the inspection for this set of equipment in each step.

If you need any support about the operation and maintenance of GN’s equipment like 3–Phase Decanter Centrifuge, please feel free to contact GN company for our engineers’ best experience and knowledge in the relevant industry. We will do our best to assist your project because just in this way we can establish a stable and long term cooperation. And we can provide on-line support and site instruction for specific situation if needed.

As a leading manufacturer of separation equipment and conveying equipment, GN always pay high attention to the product quality and consider the long-term benefits for our users. We would also like to introduce GN as a professional manufacturer in decanter centrifuge field, GN pays a lot of attention in the selection of raw materials, high-quality centrifugal casting or forging stainless steel materials are used, and for wearing parts, hard alloy protection is used.

By the way, if you are interested in our products, please check the following items of our company on Alibaba:

Decanter centrifuge

3–Phase Disc centrifuge

Sludge dewatering Screw press

Oil water separator

Centrifugal pump

Vacuum Pump

Submersible pump

Clean water is becoming more and more valuable raw materials, which is why the importance of urban sewage treatment continues to grow. The sludge from drinking water and sewage treatment must be separated as effectively as possible. At present, the industrial decanter centrifuge is considered as the latest technology of sludge dewatering and thickening, which has the characteristics of economy, energy saving and high efficiency.

GN company has more than 12 years of experience in sewage sludge treatment. We understand the special requirements of sewage treatment plant and water industry. The GN Brand has been in the industry since 2007. GN products have been exported to over 70 countries in the world. Over 70% of the products are made for international customers. GN have branch in Houston, USA and Moscow, Russia for support to our local customer. GN make different types of decanter centrifuge include Clarifying Centrifuge, Classifying Centrifuge, Thickening Centrifuge, Dewatering Centrifuge.

Sludge decanter centrifuge specially developed for the special requirements of sewage treatment plant

The main purpose of dewatering process is to minimize the volume of sludge. The reason is that every tenth increase of dry solid in sludge will reduce the cost of sludge removal. A higher dry solid content was obtained.

It not only eases the subsequent treatment process, but also improves the overall performance of the sewage treatment plant. GN company is used to compact the sludge, so that the dry solid content of the sludge is concentrated in a few percentage points.

GN decanter centrifuge can also be used for the best mud thickening of polymer based strong flocking agent. The polymer is largely removable, and the horizontal decanter centrifuge can achieve very good value.

The sewage sludge can be produced in drinking water treatment. The decanter centrifuge is used to reduce the transportation and landfill cost of sludge, increase the dry solid content, and reduce the amount of polymer required.